Female skiers likelier to injure non-dominant knee

NEW YORK (Reuters Health) - Women skiers are more likely than men to injure a knee while skiing, and a new study shows they are about twice as likely to have that injury occur to their non-dominant leg, often the left one.

The study did not go so far as to explain these inequalities, but Dr. Robert Johnson, a sports medicine physician at the University of Vermont College of Medicine said it could be caused "by a whole herd of issues."

"Anatomy, strength patterns, muscle patterns, wider pelvis...it all adds up. It's not just one factor," said Johnson, who was not involved in the research.

Earlier studies have shown that women are twice as likely as men to hurt a knee during downhill ski crashes, and three times as likely to tear the knee's anterior cruciate ligament, or ACL.

Gerhard Ruedl, lead author of the new study and a researcher at the University of Innsbruck in Austria, said he was interested in looking at whether women's knee troubles had to do with leg dominance.

The dominant leg is the one that a person prefers to kick with.

Ruedl and his colleagues collected information from close to 200 recreational skiers who had torn their ACL while skiing in Austria.

Men were just about equally likely to have injured their left knee as their right, although 87 percent of them were right-leg dominant.

Most women, 91 percent, were also right-leg dominant, but twice as many injured their left ACL as their right.

Skiing ability and physical fitness did not appear to influence the injury locations, leading the authors to conclude that the sex of the skier was responsible for the differences.

Ruedl said women have greater body asymmetry than men with regard to strength and proprioception, the sense of how the body -- in this case, the knee -- is positioned.

"Studies show that strength and proprioception is greater in the dominant compared to the non-dominant leg," Ruedl told Reuters Health by email.

This could perhaps make women more vulnerable to the strain that is put on the non-dominant knee as a skier turns.

"During a carving turn the greatest pressure is on the inside edge of the downhill (outside) ski," he said. "Our results showed that most skiers injured their ACL during a right turn where the left leg (= mostly the non-dominant leg) is the outside leg."

Ruedl and his colleagues note in their study, published in the American Journal of Sports Medicine, that four out of every 10,000 visits to a ski resort result in an ACL tear.

He recommends that to prevent injuries skiers should do strength and balance training on their non-dominant leg to reduce differences between the legs.

Johnson said he's skeptical that strength training could reduce ACL injuries for female skiers, and there have been no studies showing that working on the muscles of one leg could prevent it from being injured in a downhill wipeout.

"It makes sense that the stronger you are the less likely you are to be injured, but who has the highest incidence of ACL tears? It's ski racers," Johnson told Reuters Health.

"When you've got a two-meter lever on your leg, I'm skeptical anything will make a difference," he added.

Ruedl also said that skiers should get their bindings professionally adjusted each year and not ski faster than their skill level.